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Illinois' Sinkhole Plain: Classic Karst 
Terrain of the Midwestern United States 

Geological Field Trip Guidebook for the 12th 
Multidisciplinary Conference on Sinkholes and 
the Engineering & Environmental Impacts of Karst 
January 10-14, 2011 
St. Louis, Missouri, USA 

Samuel V. Panno and Keith C. Hackley 

Illinois state Geological Survey 

Walton R. Kelly 

Illinois state Water Survey 

Donald E. Luman 

Illinois State Geological Survey 

Guidebook 39 2011 



Institute of Natural Resource Sustainability 

Sponsored by: 

P.E. LaMoreaux & Associates, Inc. 

106 Administration Road 

Oak Ridge, TN 37830 

'"^'^■"- - -- 

Cover photograph: The incised channel (Figure 34a) showing the relationship between the sinuosity of the 
channel and the texture of the bedding plane surface. (Photograph by Samuel V. Panno.) 

© 201 1 University of Illinois Board of Trustees. All rights reserved. 

For permissions information, contact the Illinois State Geological Survey. 

Illinois' Sinkhole Plain: Classic Karst 
Terrain of the Midwestern United States 

Geological Field Trip Guidebook for the 12th 
Multidisciplinary Conference on Sinkholes and 
the Engineering & Environmental Impacts of Karst 
January 10-14, 2011 
St. Louis, Missouri, USA 

Samuel V. Panno and Keith C. Hackley 

Illinois state Geological Survey 

Walton R. Kelly 

Illinois State Water Survey 

Donald E. Luman 

Illinois State Geological Survey 

^ OEOIO^^^-' 

Guidebook 39 2011 




Institute of Natural Resource Sustainability 
William W. Shilts, Executive Director 
E. Donald McKay III, Director 
615 East Peabody Drive 
Champaign, Illinois 61820-6964 

Sponsored by: 

P.E. LaMoreaux & Associates, Inc. 

106 Administration Road 

Oak Ridge, TN 37830 

Digitized by the Internet Archive 

in 2012 with funding from 

University of Illinois Urbana-Champaign 


Abstract 1 

Introduction 1 

History of the Sinkhole Plain 1 

Geology and Hydrogeology 2 

Research in the Sinkhole Plain 2 

Karst Mapping 2 

Cave Research 4 

Groundwater Chemistry and Inorganic Contaminants 6 

Bacterial Contamination 8 

Efforts by the Monroe and Randolph County Health Departments 12 

Guide to the Route 13 

Stop Descriptions 16 

Stop 1: Falling Springs, Dupo, Illinois 16 

Stop 2: Sparrow Creek Cave Spring, Carondelet, Illinois 19 

Stop 3: Stemler Cave Woods Nature Preserve, Columbia, Illinois 20 

Stop 4: Columbia Saline Spring, Columbia, Illinois 21 

Stop 5: Camp Vandeventer, Waterloo, Illinois 23 

Stop 6: Fountain Creek Stone Bridge, Waterloo, Illinois 26 

Stop 7: Rock City, Valmeyer, Illinois 28 

Acknowledgments 29 

References 29 

Appendix: Aerial Photographs 32 


This field trip is dedicated to the men and women of 
the Monroe and Randolph County Health Departments, 
especially Joan Bade, for their valiant efforts in educat- 
ing lawmakers, the public, and industry on how to live 
in harmony with karst terrain and for strictly enforcing 
regulations for the good of the community. The field 
trip will take its participants into the heart of Illinois' 
sinkhole plain, which lies along the western flank of the 
Illinois Basin. Here, the loess- and till-covered Missis- 
sippian-age limestone bedrock has given rise to a land- 
scape of more than 10,000 cover-collapse sinkholes, 
active branchwork caves, and large picturesque springs. 
Participants will cross lands with sinkhole densities 
greater than 80 sinkholes/km- and visit a karst window, 
several large karst springs, and a saline spring. The stop 
at Falling Springs includes a 1 5-m-high waterfall dis- 
charging from a small cave along a tufa-encrusted bluff. 
The saline spring (one of at least 40 known in the Illi- 
nois Basin) has created a black, sulfide-coated elliptical 
depression due to mixing corrosion and/or the microbial 
generation of sulfuric acid. The spring discharges to a 
small stream where mats of white, filamentous, sulfide- 
oxidizing bacteria abound. The field trip participants 
will leam about the karst geology and hydrogeology 
of Illinois' sinkhole plain and the past and ongoing re- 
search involving the use of chemistry, isotopes, and an 
rRNA gene in the identification and sources of nitrate 
and bacteria in contaminated wells and springs, the use 
of stalagmites in nearby caves to study the periodicity 
of large earthquakes (some of which were generated by 
the nearby New Madrid Seismic Zone), the significance 
of saline springs in the Illinois Basin, and mapping ef- 
forts to identify and catalogue karst features in the state 
of Illinois. 


The Illinois sinkhole plain is located 
in St. Clair, Monroe, and Randolph 
Counties in the highlands of south- 
western Illinois. This area exhibits 
classic karst geology and hydrogeol- 
ogy and contains a high density of 
cover-collapse sinkholes (Figure 1 ). 
Steep bluffs up to 60 m high sepa- 
rate the highlands of the sinkhole 
plain from the lowlands of the Mis- 
sissippi River valley to the west. The 
climate is temperate, and mean an- 
nual precipitation is 102 cm (Wend- 
land et al. 1992). Bedrock in the 
sinkhole plain is Mississippian-age 
limestone overlain by a relatively 

thin layer (0 to 20 m thick) of Pleistocene-age glacial 
till and loess. The area is replete with cover-collapse 
sinkholes, large flashy springs, and large branchwork 
cave systems. Outcrops and road cuts in the area reveal 
limestone bedrock festooned with solution-enlarged 
crevices and overlain by a well-defined epikarst (Panno 
etal. 1996). 

The sinkhole plain is predominantly rural, and the dom- 
inant land use is row crop agriculture. An improvement 
in the highway system within and north of Waterloo, 
Illinois, in the 1990s, however, reduced commuting 
times to St. Louis, Missouri, which resulted in a large 
influx of people who were unprepared for the problems 
inherent in karst terrain: land subsidence and poor 
groundwater quality. However, because of karst educa- 
tion programs initiated by Joan Bade in the early 1990s 
and continued by John Wagner (Monroe and Randolph 
County Health Departments), the area's residents are 
learning to live with the vagaries of karst terrain. In ad- 
dition, the introduction of a public water system in the 
area has alleviated water quality problems for many of 
the residents. 

History of the Sinkhole Plain 

Native Americans, including the mound builders of 
the Cahokia area, inhabited southwestern Illinois for 
thousands of years prior to the arrival of French explor- 
ers in the late seventeenth century. Eventually English, 
Irish, Scottish, and Welsh settled in the area and, after 
many bloody conflicts, displaced the Native Americans. 
One of the first towns to be built was Bellefontaine 
(now Waterloo), which was initially a trading post and 
a waypoint for western expeditions (including Lewis 
and Clark's 1803 expedition). In the early part of the 

Figure 1 Aerial view of the Illinois sinkhole plain looking west across the Missis- 
sippi River valley toward Missouri. (Photograph by Joel M. Dexter.) 

nineteenth century, German immigrants who settled in 
the area worked for landowners and were paid in land. 
Because of this practice, most of the land was eventu- 
ally owned by Germans, and much of this area is still 
farmed today by their descendants (Klein 1967). At 
present, nearly 70% of land use in the sinkhole plain is 
used for row crop agriculture (U.S. Department of Agri- 
culture 1987). 

Geology and Hydrogeology 

The sinkhole plain of Illinois lies on the western flank 
of the Illinois Basin where Mississippian-age carbonate 
rocks are at and near the surface. The thin blanket of 
sediments that overlie the bedrock consist of glacial till 
overlain by loess that typically is less than 1 5 m thick 
(Herzog et al. 1994). Bedrock is Salem, St. Louis, and 
Ste. Genevieve Limestones that dip about 3 degrees to 
the east toward the center of the Illinois Basin (Figures 
2 and 3). Karstification occurs primarily in the St. Louis 
and Ste. Genevieve Limestones, which are 97% cal- 
cite; consequently, these formations are highly soluble. 
Numerous fractures in the bedrock, roughly trending 
north to south and east to west have developed into 
solution-enlarged crevices that, along with numerous 
branchwork-type cave systems, make up the shallow 
karst aquifer. These limestones outcrop along road cuts, 
quarries, and bluffs along the Mississippi River and 
subcrop beneath Pleistocene-age glacial till and loess 
deposits that range from to 15m thick within parts 
of St. Clair, Monroe, Randolph, and Jackson Coun- 
ties. The carbonate rocks dive beneath Pennsylvanian- 
age shale to the east; on the west, the sinkhole plain 
is bounded by 60- to 100-m bluffs of the Mississippi 
River and its floodplain. Structures in the area include 
the northwest-southeast-trending Waterloo- Dupo Anti- 
cline and Columbia Syncline to the north and Valmeyer 
Anticline to the south (Nelson 1999). 

Research in the Sinkhole Plain 

The Illinois State Geological Survey and the Illinois 
State Water Survey have been conducting cave and 
karst research in Illinois' sinkhole plain since the early 
1990s. The classic karst terrain in southwestern Illinois 
provides an excellent laboratory for research on karst 
features, mapping techniques, paleoclimate and cave 
formation, earthquake periodicity of the New Madrid 
Seismic Zone, groundwater contamination, background 
ion concentrations in shallow groundwater, and CO^ se- 
questration. Past and ongoing research activities in this 
area are described next. 

Karst Mapping. During 2010, Luman and Panno 
(201 1) began examining historic and recent aerial pho- 
tography acquired over the sinkhole plain. Using GIS 

(Geographic Information Systems) technology, they 
were able to digitize every sinkhole visible on aerial 
photographs and compare their locations to the closed 
depressions on current U.S. Geological Survey (USGS) 
7.5-minute topographic maps. In addition, they docu- 
mented lineaments visible on shaded relief images pro- 
duced from large-scale USGS Digital Elevation Models 
(DEMs). All of these data were compared with bedrock 
geology maps of the area and with field data on orienta- 
tions of solution-enlarged crevices, caves, and spring 

Cover-collapse sinkholes in Monroe County tend to 
form in the loess and glacial till that overlie the crev- 
iced Mississippian-age St. Louis and Ste. Genevieve 
Limestone formations (Figures 1 and 4). Sinkholes 
are concentrated in two major areas of the county, 
which are largely encompassed by the USGS Waterloo 
and Renault topographic quadrangles. In these areas, 
sinkhole densities are as high as 95/km^ (Angel et al. 
2004; Panno et al. 2008a, 2008b, 2008c) and contain 
relatively long (>10 km) to medium-length (1 to 2 km) 
caves and abundant solution-enlarged crevices. Work 
by Panno et al. (201 1) has shown that within the sink- 
hole plain, sinkhole size is proportional to the size of 
underlying crevices and conduit systems. The size and 
morphology of the cover-collapse sinkholes in this re- 
gion are directly related to water table depth and storage 
capacity of the underlying crevices and conduits. 

Sinkhole density within the Waterloo Quadrangle is 
greatest on upland areas adjacent to Fountain Creek, the 
prominent stream valley in the quadrangle. The largest 
sinkholes are situated towards the headwaters of known 
and suspected cave systems discharging into Fountain 
Creek. Shallower, smaller sinkholes are found along the 
eastern flanks and near the nose of the Waterloo- Dupo 

In the Renault Quadrangle, the underlying bedrock is 
dominated by the St. Louis Limestone with small oc- 
currences of Salem Limestone along the crest of the 
Valmeyer Anticline where no sinkholes are found in the 
overlying sediments. Dense clusters of sinkholes are 
found in the Fogelpole Cave groundwater basin, and, 
particularly along its margin, sinkholes are large and 
complex. The center of this basin is so karstified that 
a topographic low of approximately 2.5 km^ has been 
created from the resulting coalescence of the sinkhole 
features (Figure 5). 

Preliminary results by Luman and Panno (201 1) have 
shown that the closed depressions on current USGS 
7.5-minute topographic maps miss about 30% of the 
sinkholes that are visible on aerial photographs, mainly 

Srnkhole areas 

O Field Stop Locations 
Stop 1 (Falling Springs) 
Stop 2 (Sparrow Creek Spring Cave) 
Stop 3 (Stemler Cave Woods Nature Preserve) 
Stop 4 (Columbia Saline Spring) 
Stop 5 (Camp Vandeventer) 
Stop 6 (Fountain Creek Stone Bridge) 
Stop 7 (Rock City) 

1 2 3 

4 mi i 
1 1 J, 

1 1 1 1 1 1 1 1 ( 1 1 
12 3 4 5 

'1 N 
6 km 1 

j Pennsylvanian 

1 Psp Shelbum-Patoka Fms 

1 Pc Carbondale Fm 

J R Tradewater Fm 


Mpl Lower Pope Group 

Msg Ste Genevieve Ls 

„ Msl St, Louis Ls 

{Aws- Warsaw Fm and Salem Ls 

in western IL 

flS^ Meppen Ls. Fern Glen Fm, 

Burlington-Keokuk Ls 


Om Maquoketa Fm 

i Ok Kimmswick Ls and Decorah Fm 

[ Op Platteville Group 

^Oa Ancell Group 

Figure 2 The Illinois sinkhole plain showing the distribution of karst terrain, the structural features present, and major rock units 
(modified from Luman and Panno 201 1 ). Abbreviations; Fm, Formation; Ls, Limestone. 


















1 / 1 

1 1 1 


1 1 1 

1 1 

1 1 1 

1 1 

1 1 1 

1 1 / 

/ 1 / 

II 1 

1 1 1 

1 1 / 1 

1 1 1 

/ / 1 


1 / 1 / 

/ 1 / 1 

1 1 ■ 1 

1 A 1 A 1 

1 A A 1 A 

A I A 1 A A 

1 A 1 1 A 

1 A 1 A 1 

1 A 1 A 1 A 

1 - 1 - 1 

_ _ _ 

-EI -El-El -il 

— 1 — 1 — 

Aux Vases Sandstone 

Ste. Genevieve Limestone 

St. Louis Limestone 

Salem Limestone 

Warsaw Formation 
Keokul< Limestone 
Burlington Limestone 

Fern Glen Formation 

I . T 

I — I 


;'■.;•;'•.! •'■;.■-.: r" 


^y^/ l 

Kimmswick ("Trenton") Limestone 

Decorah Formation 

Plattin Limestone 

Joachim Dolomite 

St. Peter Sandstone 

Everton Formation 

Figure 3 Generalized stratigraphic column of the Middle 
Ordovician and Middle Mississippian strata in the field 
trip area (Weibel and Panno 1997). 

because many sinkholes are shallower than the 
typical 10-foot contour interval used on large-scale 
USGS topographic maps. Luman and Panno (201 1) 
identified over 13,000 sinkholes from aerial photogra- 
phy, which is about 3,000 more than previous mapping 
by Panno et al. (1996). Preliminary results of work on 
lineaments in the sinkhole plain revealed two dominant 
lineament directions: roughly north-south and east- 
west; these correspond to the orientation of solution- 
enlarged crevices of the area (Panno, unpublished data). 

Cave Research. The sinkhole plain is home to the 
three longest known caves in Illinois: Fogelpole Cave, 
Illinois Caverns, and Stemler Cave (Figure 6). Speleo- 
thems in the first two caves and Pautler Cave, a shorter 
cave just west of Waterloo, Illinois, have been found 
to contain information on paleoclimatic conditions and 
earthquake activity within the Midwest. 

Panno et al. (2004b) found that the timing of deposition 
of diamicton and silty, fine-grained sediments within 
secondary passages of Illinois Caverns and Fogelpole 
Cave could be determined using carbon- 14 dating 
techniques. The sediments were remnants of flood de- 
posits that had been preserved. The 6'^C of the organic 
carbon within the sediments yielded information as to 
the types of vegetation present on the land surface be- 
tween 42,500 years before present (BP) and the present. 
Results of this work showed that the rate of sediment 
accumulation in the cave was positively correlated with 
a higher proportion of drought-tolerant C^-type vegeta- 
tion. That is, when climate was drier, vegetation was 
less and erosion was greater during rain events. Based 
on these data and mineralogy data indicating most of 
the cave sediments were from relatively deep soil hori- 
zons on the surface, Panno et al. (2004b) suggested that 
these rainfall events during dry periods probably initi- 
ated sinkhole formation and enlargement in the area. 
Subsequent work, using incision rates within the main 
passages of the caves adjacent to filled secondary pas- 
sages, suggested that the caves of southwestern Illinois 
were initiated by meltwaters of the Illinois Episode of 
glaciation (Panno et al. 2004a). Paleoclimate research 
involving stalagmites from these caves and caves in 
southern Indiana is ongoing and is yielding additional 
information on the relationship between Pleistocene 
glaciation and speleogenesis (Chirienco et al. 2010). 

An investigation into the origin of small white speleo- 
thems in caves of the Illinois sinkhole plain and south- 
eastern Missouri (Figure 7) revealed that speleothem 
growth was initiated by major seismic events related to 
the New Madrid Seismic Zone (NMSZ) (Panno et al. 
2009). Crevices and/or fractures leading to the caves 
from the epikarst were apparently enlarged by the earth- 

Figure 4 The excavation of a 100-m diameter sinkhole revealed a narrow crevice in the exposed St. Louis Limestone bedrock 
that leads to a somewhat wider crevice. The wider crevice led down, about 5 m, into a small cave about 0.3 m high and 0.6 m 
wide through which runoff from rainwater and snowmelt flows (Panno et al. 2009). 

quakes, allowing soil water and perched groundwater to 
seep into the underlying caves. The initiation of white 
stalagmites was temporally related to the 1811-1812 
NMSZ earthquake series. The ages of stalagmites 
on which the white stalagmites were growing corre- 
sponded to prehistoric NMSZ earthquakes known from 
the dating of nearby liquefaction features (e.g., Tuttle 
et al. 1999). A subsequent investigation revealed the 
existence of the white stalagmites and associated older, 
earthquake-related stalagmites in other midwestem 
states in the vicinity of the NMSZ (Panno et al. unpub- 
lished data). Age-dating has the potential to document 
additional paleoseismic events in the Midwest and in 
other seismically active areas of the world. 

The caves of the sinkhole plain are the sole habitat of 
the Illinois cave amphipod {Gammanis acherondytes), 
a federally endangered species. The amphipod was re- 
ported to be present in both Illinois Caverns and Stem- 
ler Cave as well as a few other caves in the sinkhole 
plain in the 1970s (Peck and Lewis 1978). Subsequent 
studies failed to locate the amphipod in Stemler Cave 
after 1995 (Webb 1995). Using those data, Panno et 
al. (2006) compared the aqueous environment of Il- 
linois Caverns with that of Stemler Cave to determine 
environmental differences within the caves. They found 
that the water flowing through Stemler Cave during low 

flow conditions was low in dissolved oxygen due to dis- 
charge from private septic systems within the ground- 
water basin. No such conditions were present within 
the Illinois Caverns streams. The authors speculate that 
the near-hypoxic conditions within the Stemler Cave 
groundwater basin may have given the competitive ad- 
vantage to other invertebrates within the groundwater 
basin. For an in-depth study of macroinvertebrate bio- 
diversity in caves and springs in the sinkhole plain, see 
Webb etal. (1998a). 

Field trips to the Illinois sinkhole plain would ordinarily 
include a trip to Illinois Caverns (Frankie et al. 1997, 
Panno et al. 1999, 2004a), which is the second larg- 
est cave in the state and is typical of the area's caves 
(Figures 8 and 9). Illinois Caverns is a branchwork- 
type cave that formed along bedding planes within the 
St. Louis Limestone. Unfortunately, the occurrence of 
White Nose Syndrome in bats of caves, now extending 
from eastern Canada and New York to Missouri, has 
resulted in the closure of Illinois Caverns and many 
other caves throughout the midwestem United States 
(Frick et al. 2010). White Nose Syndrome in bats first 
appeared in the Northeast in 2006. The condition causes 
white patches on the muzzle and arms of bats and has 
been attributed to a psychrophilic (cold-tolerant) fun- 
gus named Geomyces destrnctans. The fungus disturbs 

2 mi 


3 km 


Figure 5 Sinkholes coalesce within the Fogelpole Cave groundwater basin to the point where sinkhole density reaches satura- 
tion, resulting in an overall lowering of the elevation of the topography (modified from Luman and Panno 201 1). 

hibernating bats, resulting in loss of critical fat reserves 
necessary for survival during hibernation (Frick et al. 
2010). The extinction of several bat species is predict- 
ed. The source of the fungus is as yet unknown, but it 
may be spread by both bats and humans. Consequently, 
caves across the East and Midwest have been closed 
to humans to protect the remaining bat colonies and/or 
slow the spread of the fungus. 

Groundwater Chemistry and Inorganic Contami- 
nants. The chemical composition of groundwater in 
the sinkhole plain is primarily a calcium-bicarbonate- 
type water. During water quality investigations of the 
springs and wells between 1 994 and 2000, the pH 
of samples from the springs ranged from 6.5 to 8.5; 
samples from the wells ranged from 6. 1 to 7.2 (Panno 
et al. 1996, Hackley et al. 2007). Dissolved organic 

Figure 6 One of three large caves in Monroe County, Illinois 
Caverns is a branchwork-type cave with an active stream 
channel that drains the Illinois Caverns groundwater basin. 
(Photograph by Joel M. Dexter.) 

Figure 7 Small white stalagmites in Illinois Caverns tend to 
grow in clusters either by themselves or on top of older sta- 
lagmites. Most of these stalagmites were initiated during the 
New Madrid Seismic Zone earthquake series of 1 8 1 1 - 1 8 1 2 
(Panno et al. 2009). 

carbon from the springs ranged from 1 .7 mg/L to nearly 
14 mg/L, which is more typical of surface water than 
groundwater (typically <2 mg/L for groundwater). 
Parameters such as temperature, fluoride, chloride, and 
carbon isotopes (S'-'C) fluctuated seasonally for most of 
the springs sampled, indicating a relatively rapid con- 
nection between the karst aquifer and the influx from 
surface water. Tritium concentrations in spring water 
from the study area were between about 4 and 8 tritium 
units, which were similar to local precipitation values, 
also indicating recent recharge from surficial sources 
(Hackley et al. 2007). Considering the relatively rapid 
influx of recharge water from the surface environment 
to the shallow karst aquifer, it is not surprising that 
much of the groundwater in the sinkhole plain has been 
contaminated by anthropogenic sources. Both spring 

Figure 8 The entrance to Illinois Caverns, as viewed from the 
cave floor, is an east-west-trending solution-enlarged crevice 
at the bottom of a sinkhole (Panno et al. 2004a). 

Figure 9 Entrance to the Canyon Passage at Illinois Caverns 
revealing the active stream passage that flows through the 
cave (Panno et al. 2004a). 

and well water in the sinkhole plain contain elevated 
concentrations of nitrate nitrogen (NO,-N), pesticides, 
and bacteria (Panno et al. 1996, Webb et al. 1998a, 
Hackley et al. 2007, Kelly et al. 2009). 

In the 1 990s, nearly half the residents of the sinkhole 
plain area in southwestern Illinois got their drinking 
water from uncased bedrock wells in the karst aquifer 
at depths of 20 to 100 m. Water quality investigations 
estimated that about 1 8% of the wells in this region had 
NO3-N concentrations greater than the U.S. Environ- 
mental Protection Agency drinking water standard of 10 
mg/L. All of the springs sampled and 50% of the wells 
had NO3-N concentrations greater than background lev- 
els of -2.2 mg/L (Panno et al. 2006), suggesting consid- 
erable input of NO3-N from sources other than natural 
soil organic matter (Hackley et al. 2007). The sinkhole 
plain region is dominated by row crop agriculture, but 
during the last two decades the area has undergone a 
high degree of urban development. Between 1 997 and 
2003, more than 20,000 ha were urbanized in the seven 
counties incorporating the sinkhole plain and karst 
aquifer region of southwestern Illinois (Southwestern 
Illinois Resource Conservation and Development, Inc. 
2005). Thus, the major sources of nitrate other than nat- 

urally occurring soil organic matter include agricultural 
fertilizers, livestock facilities, and sewage and septic 
discharge. Ten springs were sampled for six consecu- 
tive seasons and 1 7 wells for two seasons to examine 
the variation in geochemical parameters and determine 
the major source of elevated NO3-N in the groundwater 
of the sinkhole plain (Hackley et al. 2007). Nitrate-N 
concentrations in the springs ranged from 1.7 to 7.5 
mg/L. The wells showed much greater variations, rang- 
ing from below detection limits to 81 mg/L. Figure 10 
shows NO3-N concentration versus depth for the wells. 
The shallowest wells contained the greatest NO^-N con- 
centrations, but even very deep wells contained concen- 
trations well above background levels. Those samples 
containing elevated NO^-N typically contained elevated 
chloride also, suggesting septic or livestock contamina- 
tion (Figure 1 1 ). 

Nitrogen and oxygen isotopes of the nitrate were 
measured for samples collected from both springs and 
wells. The results for spring samples indicated the ni- 
trate source was dominated by fertilizer and/or soil or- 
ganic matter nitrogen and that some denitrification had 
occurred in the karst environment (Hackley et al. 2007). 
Many of the nitrate isotopic results for the wells were 
similar to the results for the bulk of the samples from 
springs; however, several of the well samples had 8'-N 
and 6'^0 values that were shifted toward values more 
representative of septic and livestock sources (Figure 
12). For those wells with the greatest NO-,-N concentra- 
tions (>13 mg/L), the data indicated that the source was 
primarily from septic and livestock waste. Nitrate in 
wells with NO3-N concentrations between about 2 and 
12 mg/L was primarily from fertilizer and soil organic 
matter. The isotopic results of a few of the well samples 
also showed significant denitrification (Hackley et al. 

Bacterial Contamination. Within and near the 
sinkhole plain, 16 springs, 64 domestic wells, and the 
Illinois Caverns cave stream were sampled for bacteria 
at multiple times between 1994 and 2000 (Kelly et al. 
2009). Bacterial colonies in spring water samples in- 
cluded bacteria commonly found in soils and surficial 
aqueous environments, and enteric bacteria. All spring 
and stream samples had detectable concentrations of 
total coliforms (TC) and total aerobic bacteria (TA). 
More than 92% of the spring water samples and streams 
in Illinois Caverns had detectable concentrations of 
both fecal coliforms (FC) and fecal enterococci (FE) 
(Kelly et al. 2009). Counts for TA were commonly >3 
million colony-forming units (cfu/100 ml); TC typi- 
cally ranged from a few 100 to >4,800 cfu/100 ml; FE 
were from to >4,800 cfu/100 ml; and FC were from 
to >2,400 cfu/100 ml (Hackley et al. 2007). Illinois 



Z 40 








■ wells 


Regulatory limit 



- background 





. ■ 






80 100 

Depth (m) 





Figure 10 Nitrate (NO,-N) concentrations versus depth for wells sampled in southwestern Il- 
linois (modified from Hackley et al. 2007). 









Chloride (mg/L) 





■ ■ 


' -^^^F 


•» ^" 

♦ septics 

% ■ 

■ wells 

A springs 

■ hog waste 



10 100 

Nitrate and/or Ammonium N (mg/L) 



Figure 11 Chloride versus nitrate and ammonium concentrations (total inorganic nitrogen 
measured) of wells, springs, septic systems, and livestock facilities (modified from Hackley et al. 

water quality regulations require that water suitable for 
primary contact must not have an average concentration 
of FC >200 cfu/100 mL for five samples collected over 
a period of 30 days. Furthermore, 10% of the samples 
may not have concentrations exceeding 400 cfu/100 mL 
(Illinois Environmental Protection Agency-Illinois Pol- 
lution Control Board 1999). Figure 13a shows FC con- 
centrations found in 10 springs. Bacterial contamination 
occurred in the springs and cave streams throughout 
the year (Figure 13a), suggesting that wastewater dis- 
charge, which is not seasonally variable, is a greater 

problem than livestock waste. Hog manure is applied to 
fields only in the fall and spring, and, during the winter, 
cattle manure is less subject to decomposition and mo- 
bilization and thus less likely to enter the aquifer/cave 
systems (Kelly et al. 2009). 

The types of bacteria in well-water samples were 
similar to those found in the springs, but at lower con- 
centrations. Tests for TA detected them at least once in 
58 of the 64 wells, suggesting that groundwater in the 
capture zones of these wells was generally oxygenated. 




10 -- 





fertilizer NO 

Total N (mg/L) 

• 0-3.0 

• 3.1-6.0 

• 6.1-9.0 

• 9.1-12.0 

• 12.1-15.0 

• 15.1-18.0 
% 18.1-21.0 

^P septic and 

Solution-: :8-NH, 
and Urea 

O NW-5 ^NW-17Seplic aM-6 

Figure 12 Isotopic composition of nitrate (orange) and 
possible sources of nitrate in well-water samples including 
fertilizer, septic systems, and livestock waste. Predominant 
domains of nitrate sources and typical trend for denitrifica- 
tion (arrows) are included. The 5"*0 of nitrate that would be 
expected from reduced forms of nitrogen was calculated to 
depict the composition expected for nitrification processes. 
The calculated values are in excellent agreement with the 
measured 8"*0 NO, for the septic system sample NW-1 7 
(from Hackley et al. 2007). 

The TC were detected at least once in 63% of the wells, 
but at concentrations typically much lower than in the 
spring and cave samples. FC or FE were detected at 
least once in 23 wells, generally at low concentrations. 
About half of the detections were <10 cfu/100 mL, and 
the maximum concentration was 198 cfu/100 mL. The 
state and county drinking water regulations require <80 
cfu/100 mL for TC and no FC in residential well water. 
All bacterial indicators were less likely to be detected, 
and concentrations were lower, in wells in non-karst 
than in karst and covered karst areas. Wells located in 
areas with livestock had the highest concentrations of 
FE, and the water chemistry was indicative of fecal 
contamination (elevated NO^-N and CP). Shallow wells 
were more likely to have detectable TC, FC, and FE 
and at higher concentrations regardless of terrain; wells 
<20 m deep (all in covered karst) were the most vul- 
nerable (Figure 13). The inverse relationship between 
well depth and FE indicates that deeper groundwater 
is somewhat protected from surface contamination. 
However, TC, FC, and/or FE were found in 10 of the 18 
wells in karst or covered karst that were >100 m deep, 
indicating shallow groundwater was entering the well 
bore (Kelly et al. 2009). 

_ 10,000 

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Figure 13 (a) Distribution of fecal coliform concentrations in 
water samples from springs in southwestern Illinois. Enlarged 
symbols are springs visited on the field trip (modified from 
Kelly et al. 2009). (b) Total coliforms versus well depth, 
(c) Fecal coliforms and fecal enterococci versus well depth. 
Symbols touching the dotted line represent samples with total 
coliform concentrations greater than the upper detection limit 
(UDL) of 4,000 cfu/100 mL (modified from Kelly et al. 2009). 


Figure 14 A conceptual model of the hydrogeology and redox conditions of the karst aquifer in 
the sinkhole plain for a groundwater basin (from Kelly et al. 2009). 

A negative association was observed between TC and 
well casing length in the karst region, suggesting that 
well construction practices in areas with significant 
dissolution features can contribute to bacterial con- 
tamination of the aquifer. Drilled wells are often cased 
and grouted only through the unlithified sediments and 
into the top of bedrock; 16 of 40 wells for which data 
were available were cased into the bedrock 3 m or less. 
This construction practice allows wells to be exposed to 
shallow groundwater that often migrates through con- 
duits in the bedrock, possibly resulting in the mixing 
of contaminated shallow groundwater with uncontami- 
nated or less contaminated groundwater from deeper 
bedrock (Panno et al. 1996). 

When comparing water quality among springs, caves, 
and wells in the study area, it is important to consider 
the differences in hydrogeological and geochemical 
conditions. Springs are outlets for all shallow ground- 
water in a particular karst groundwater basin and rep- 
resent a mixture of water throughout the basin, often 
from areas with different land uses. Thus, although 
contamination from any point in the groundwater ba- 
sin may be detected in the spring discharge, it will be 
diluted by water coming from uncontaminated areas. 
Groundwater collected from wells generally represents 
a smaller source area and will have longer residence 
times. Contaminated wells were less likely than springs 
to show signs of dilution. Thus, wells in the study area 
generally had lower NO,-N concentrations than springs 
did (median 0.66 mg/L vs. 3.8 mg/L), but a wider range 

of values. Sixteen percent of well samples had NO^-N 
greater than 10 mg/L; none of the spring or cave sam- 
ples exceeded 10 mg/L. 

Kelly et al. (2009) developed a conceptual model of 
the region (Figure 14). In covered karst areas and typi- 
cally along the margins groundwater basins, the water 
table is shallow, and wells finished above the bedrock 
are vulnerable to surface contamination. For wells <20 
m deep, median NO,-N and Cf concentrations were 
12.2 and 24 mg/L, respectively; in deeper wells, median 
NO3-N and Cr concentrations were 0. 19 and 12 mg/L. 
Pesticides and FC were detected in 60% and 3 1 % of the 
shallow well samples, respectively, and 20% and 7% of 
the deeper well samples. In karst areas, the water table 
is within the bedrock, and there were no wells shallow- 
er than 20 m. Groundwater in the karst areas is gener- 
ally well oxygenated. At least four of the wells sampled 
in the karst setting intersected a large crevice or cave. 
In covered karst areas, the groundwater is generally less 
oxygenated and often anoxic (Figure 14). Conditions 
are generally fully anoxic in the bedrock in the covered 
karst region. The median redox potential value in cov- 
ered karst wells deeper than 20 m was 100 mV lower 
than in karst areas. 

To help distinguish the source of bacterial contamina- 
tion of groundwater in the sinkhole plain, we recently 
initiated a study to identify fecal sources using the 
Bacteroides-Prevotella 16S rRNA gene as part of a new 
molecular method termed hierarchical oligonucleotide 


primer extension (HOPE) (Hong et al. 2009). The 
HOPE method has been successfully demonstrated to 
identify and distinguish sources of fecal contamina- 
tion among human, cow, pig, and dog feces in a rapid 
and throughput manner. As part of that investigation, 
10 springs were sampled in 2009, including Falling 
Springs, Sparrow Creek, and Camp Vandeventer, which 
are being visited on this field trip. Of the eight springs 
that were contaminated with fecal bacteria, one was 
identified as being predominantly from humans (Spar- 
row Creek), two predominantly from pigs (including 
Falling Springs), two predominantly from pigs with 
possibly some human sources (including Camp Vande- 
venter), and three from a combination of humans, pigs, 
and cows. These results generally compared well with 
our predictions based on known land uses, but, for 
two of the sites, the source tracking method gave un- 
expected results. This study was recently expanded to 
look at karst water resources in Wisconsin, Kentucky, 
and Missouri. 

Efforts by the Monroe 
and Randolph County 
Health Departments 

In the early 1 990s, Joan Bade of the Monroe and Ran- 
dolph County Health Department recognized the prob- 
lems associated with the karst terrain and well-water 
quality in the Illinois sinkhole plain. These problems 
were exacerbated in the mid-1990s when Route 3 
through Waterloo, Illinois, was expanded to a four-lane 
highway, which significantly cut the commute time 
to and from St. Louis, Missouri, and resulted in many 
new residents moving to the area. As head sanitarian, 
Joan Bade garnered help from the Illinois State Geo- 
logical Survey, the Illinois Environmental Protection 
Agency, the Illinois State Health Department, and local 
schools and led a very successful campaign to educate 

the people of Monroe and Randolph Counties about the 
problems of karst terrain. With the support of these or- 
ganizations, she organized and led annual field trips and 
conferences to spread the word about the problems to 
regulators and lawmakers. She strictly enforced existing 
regulations regarding the siting of septic systems and 
requests for housing construction in the face of consid- 
erable opposition. She was instrumental in changing 
weak regulations regarding the siting of septic systems 
and permitting for housing and well construction. In ad- 
dition. Bade successfully acquired grants from the Illi- 
nois Environmental Protection Agency and hired a karst 
educator to educate the citizens of the area. John Wag- 
ner, Bade's assistant beginning in 1995, later became 
head sanitarian after Bade took a job at the Illinois De- 
partment of Natural Resources. The health department 
is now split into a department for each county. Wagner 
is head of both Monroe and Randolph County's health 
departments and continues, with the help of Adrian 
Coring, to educate the citizens of the sinkhole plain and 
to enforce regulations. Today, the term "karst terrain" 
is well-known in the area, and the citizens understand 
its meaning and its implications for water quality, land 
stability, and flooding. 

During the late 1990s and early 2000s, a municipal 
water system was made available to many of the resi- 
dences of the sinkhole plain, alleviating persistent water 
quality problems for most residents. Unfortunately, be- 
cause residents no longer have to worry about their wa- 
ter supplies, they are now less concerned about ground- 
water protection (John Wagner, personal communica- 
tion 2010). Some homeowners still have to contend 
with sinkholes and subsidence beneath and adjacent to 
their houses, although reports of this occurring are rare, 
probably because of the difficulty inherent in selling a 
house prone to land subsidence (Panno et al. 2008d). 



Start: Holiday Inn St. Louis-Southwest (Viking), 10709 Watson Rd., St. Louis, Missouri 63127 (877-410-6681). Set 
your odometer to zero. 

Miles Miles 

to next from 

point start 

0.4 0.4 Start by going west on Watson Road/Missouri 366 toward Sunset Office Drive. 

6.9 7.3 MERGE onto 1-270 south toward Memphis. 

8.4 15.7 1-270 South becomes 1-255 East crossing into Illinois. 

0.3 16.0 Take Exit 9 toward Dupo. 

2.4 18.4 MERGE onto Industrial Drive. 

0.3 18.7 TURN SLIGHT RIGHT onto Falling Springs Drive. 

0.08 1 8.8 TURN RIGHT onto LePere Lane. 

0.01 1 8.8 2002 LePere Lane, Dupo, Illinois, is on the left. 

Stop 1: Falling Springs, Dupo, Illinois. 

0.2 19.0 Leave Stop 1 . Go northeast on LePere Lane toward Falling Springs Drive. 

0. 1 19.1 TURN SLIGHT RIGHT to stay on LePere Lane. 

1.0 20.1 LePere Lane becomes McBride Avenue. 

1.8 2 1 .9 TURN RIGHT onto Stolle Road. 

4.0 25.9 TURN SLIGHT RIGHT onto Triple Lakes Road. 

0.01 25.9 7508 Triple Lakes Road, East Carondelet, Illinois, is on the left. 

Stop 2: Sparrow Creek Cave Spring, East Carondelet, Illinois. 

0.9 26.8 Leave Stop 2. Go southeast on Triple Lakes Road/County Road P53 toward Black Oak Lane. 

Continue ahead. 

1 .6 28.4 TURN RIGHT onto Bluffside Road/County Road 0430 East. Continue to follow Bluffside 



0.6 29.0 TURN LEFT onto Stemler Road. CAUTION: Portions are unpaved. 

0.01 29.0 2016 Stemler Road, Columbia, Illinois, is on the right. 

Stop 3: Stemler Cave Woods Nature Preserve, Columbia, Illinois. 

0.4 29.4 Leave Stop 3. Go east on Stemler Road toward Country Estates Drive. CAUTION: Portions 

are unpaved. 

0.6 30.0 TURN RIGHT to stay on Stemler Road. 

1 .0 3 1 .0 TURN RIGHT onto Triple Lakes Road/Country Road P53. 

0.9 3 1 .9 TURN LEFT to stay onto Triple Lakes Road/Country Road P53. 

3.0 34.9 TURN RIGHT onto Illinois 158. 

0.3 35.2 TURN SLIGHT RIGHT onto Illinois 3 going south. 

1 .3 36.5 TURN RIGHT onto Hill Castle Road, Columbia, Illinois. 

0.01 36.5 Continue ahead to Columbia Saline Spring. 

Stop 4: Columbia Saline Spring, Columbia, Illinois. 

1.3 37.8 Leave Stop 4. Go north on Hill Castle Road toward Hill Castle Drive. 

7.0 44.8 TURN RIGHT onto Illinois 3, going south. 

2.3 47. 1 TURN RIGHT onto Park Street/Illinois 1 56. Continue ahead. 

0.8 47.9 TURN SLIGHT RIGHT onto Trout Camp Road, Waterloo, Illinois. 

0.01 47.9 Continue 0. 1 mile past Copperhead Hill Lane to Camp Vendeventer. 

Stop 5: Camp Vandeventer, Waterloo, Illinois. 

0.8 48.7 Leave Stop 5. Head southeast on Trout Camp Road toward Copperhead Hill Lane. 

0. 1 48.8 TURN SLIGHT LEFT onto Illinois 1 56. 

0.01 48.8 3699 Woodpecker Lane, Waterloo, Illinois, is the next stop. 


Stop 6: Fountain Creek Stone Bridge, Waterloo, Illinois. 

4.8 53.6 Leave Stop 6. Proceed west on Illinois 156 toward Trout Camp Road. 

1.8 55.4 Illinois 156 becomes East Main Street. 

0.5 55.9 TURN SLIGHT RIGHT onto Quarry Road. 

0.3 56.2 TURN RIGHT onto Limestone Lane. 

0.03 56.2 TURN RIGHT onto Boulder Boulevard. 

0.01 56.2 1423 Boulder Boulevard, Valmeyer, Illinois, is on the left. 

Stop 7: Rock City, Valmeyer, Illinois. 

0.03 0.03 Set odometer to zero. To return to the hotel, go west on Boulder Boulevard toward Limestone 


0.4 0.4 TURN LEFT onto Limestone Lane. 

12.8 13.2 TURN RIGHT onto Bluff Road. 

0.8 14.0 Continue ahead to go onto Bluff Road/Country Road 6. Continue to follow County Road 6 


0. 1 14.1 Country Road 6 North becomes Palmer Road. 

0.5 14.6 MERGE onto Illinois 3 North via the ramp on the LEFT toward 1-255. 

6.8 21 .4 MERGE onto 1-255 South via the exit on the LEFT toward St. Louis County crossing into 


5.2 26.6 MERGE onto 1-270 North. 

1 .0 27.6 EXIT on Exit 5 A onto Missouri 366 East/Watson Road. 

0.6 28.2 TURN SLIGHT RIGHT onto Watson Road/Missouri 366 East. 

0.01 28.2 The Holiday Inn is 10709 Watson Road. 



Stop 1: Falling Springs, Dupo, Illinois 

Appendix Figures A 1 and A2 show the location of Fall- 
ing Springs as it appears in 2005 USGS National Aerial 
Photography Program (NAPP) aerial photographs and 
USDA 1940 Agricultural Adjustment Administration 
(AAA) aerial photographs. Both photographs reveal 
the karst terrain on the highlands above the spring and 
development of the area. For example, the quarry to the 
southwest was not in operation in 1 940. Also, whereas 
sinkholes are prominent within the forested areas of the 
2005 photograph (acquired under leaf-off conditions), 
the sinkholes in agricultural fields are prominent in the 
1940 photograph (acquired under leaf-on conditions 
and during a drought). 

Falling Springs is a perched cave spring that discharges 
from a 1- by 2-m cave along a bedding plane about 
midway up a steep, 50-m bluff (Figure 15). The bluff is 
predominantly Mississippian-age St. Louis Limestone 
capped by several meters of Ste. Genevieve Limestone 
(Zakaria Lasemi and Rodney Norby, ISGS geologists, 
personal communication 1998) and is located along the 
eastem edge of the Mississippi River Valley. The spring 
water cascades over a reddish black tufa deposit that 
has encrusted local vegetation. Tufa is a porous deposit 
of calcium carbonate that is associated with calcareous 
springs and seeps. 

Historically, the spring was used as a source of fresh 
water. Among other uses, during the late 1 800s and 
early 1900s, the spring supplied water to steam loco- 
motives that served nearby limestone quarries (Figure 
15). More recently, a 30-cm-wide iron trough near the 
base of the tufa apron was installed in about 1970 and 
currently supplies water to adjacent fish ponds (Figure 
16a). Based on the fact that the tufa has now grown 
over the trough and extends beyond it by about 45 cm, 
the growth rate of the tufa near the base of the apron is 
approximately 2 cm/yr. Precipitation of minerals from 
the spring water is so rapid that leaves from the fall 
may be found totally encrusted with calcite before they 
get washed away by spring time flooding. Tufa on the 
right of the apron (Figure 16a) is continually removed 
with a backhoe so that water continues to fill the trough. 
Other small cave openings are visible in the bluff at 
approximately the same stratigraphic horizon as that 
of Falling Springs. Most of the openings have little or 
no flow even after a heavy rainfall (Bowman and Reed 
1907). However, residents in the area report that an 
opening just to the north of Falling Springs discharges 
sediment-laden water during and immediately follow- 

ing large recharge events (Cliff LePere, owner, personal 
communications 2010). 

Beneath a dry cave opening immediately to the south 
of Falling Springs is a tufa deposit that is far larger than 
that of the tufa apron of Falling Springs. In fact, sub- 
sequent to deposition of the southem tufa deposit, dis- 
solution by dilute spring water produced a small tunnel 
through the tufa deposit (Figure 16b). Preliminary re- 
sults of carbon- 14 dating of fossil invertebrates fi^om a 
similar tufa deposit at the base of Terry Spring, located 
about 15 km to the south along the Mississippi River 
bluff, yielded an age of 10,840 ± 170 years BP (Webb 
et al. 1998a), suggesting tufa deposition near the end 
of the Wisconsinan glaciation and the beginning of the 
Holocene (Webb et al. 1996). 

The chemical composition of water from Falling 
Springs is controlled by the dissolution of limestone. 
The calcium-bicarbonate groundwater is saturated, 
for most of the year, with respect to calcite, aragonite, 
dolomite, and quartz (Panno et al. 1999). Aeration, 
agitation, and change in the partial pressure of carbon 
dioxide (CO,) of the spring water results in the release 
of CO, from the water and causes the tufa to precipitate 
along the bluff face (Herman and Lorah 1987). The 
aeration of the spring water along the bluff causes iron 
oxyhydroxide to precipitate, darkening the tufa apron 
(Figures 15 and 16b). 

Davis et al. (1989) examined the tufa deposit and its bi- 
ota in detail and described the deposit, which starts out 
on a ledge a few meters below the mouth of the cave, 
as a 1 -m-high cone-shaped mound that fans out like a 
curtain between the ledge and the bottom of the bluff, 
becoming more massive near the base. The tufa is about 
5 m wide and 5 cm thick at the lip of the ledge and 7 m 
wide and up to 55 cm thick at the bottom.They reported 
that the most dominant organism on the apron was blue- 
green algae, the most abundant species being Phormi- 
diiim incnistatum. Moss and a bacteria-laden mucilage 
were also observed on the tufa. The strands of algae and 
moss are apparently being encrusted by calcite, forming 
tangled clusters of parallel to subparallel, finger-like 
projections that make up the apron. X-ray fluorescence 
analysis determined that calcium, magnesium, silicon 
dioxide, and iron were dominant at the surface of the 
tufa (Davis et al. 1989). 

Discharge from the spring at base flow is clear and was 
measured at approximately 38 L/s (Panno and Weibel 


Figure 15 Falling Springs is a perched cave spring near Dupo, Illinois, that discharges from a bedding 
plane cave in the upper St. Louis Limestone. The perched cave spring bears witness to the rapid entrench- 
ment of the Mississippi River valley, probably during the Pliocene to early Pleistocene Epoch. In the early 
1900s, the spring was used to supply water for domestic use and for steam locomotives (inset). The railroad, 
steam locomotives, and water towers are gone today, but the spring now provides water for nearby fishing 
ponds (from Panno et al. 2009). 


Figure 16 (a) The base of Falling Springs showing a 30-cm-wide trough that was installed by Cliff 
LePere (right) and his brother in 1970 to channel water to nearby fish ponds. The tufa has grown 
completely over the trough on the left, but has been trimmed back by a backhoe on the right (note 
teeth marks of backhoe shovel), (b) Dissolution conduit in tufa adjacent to Falling Springs formed 
by very rapid recharge in the upland area, possibly during a major climate change event. (Photo- 
graphs by Samuel V. Panno.) 


1999). During and following heavy rains, discharge 
typically is laden with suspended solids, and the vol- 
ume of discharge appears to be one to two orders of 
magnitude greater than that of base flow. As with most 
springs in the sinkhole plain, water quality from Falling 
Springs is extremely poor. The water is contaminated 
with TC, FC, and FE derived from both natural and 
anthropogenic sources. Given the likely recharge area 
of the spring, bacteria sources probably include wastes 
from livestock, pets, and private septic systems as well 
as naturally occurring bacteria. Bacterial concentrations 
of water samples from the spring contained total aero- 
bic bacteria counts of 300,000 cfu/100 mL of water, TC 

counts of 4,000 cfu/100 mL, and FC and FE counts of 
12 and 120 cfu/100 mL, respectively (Panno et al. 2001). 

Based on the chemical composition of the water issu- 
ing from Falling Springs at base flow, it is apparent that 
the water is a mixture of highly reduced groundwater 
oversaturated with respect to calcite and lesser amounts 
of bacteria-laden shallow groundwater. Given the abun- 
dance of suspended sediments in the spring water under 
high flow conditions, it would appear the dominant 
source of water during high flow comes via sinkholes 
(Figures 17 and 18). Sinkhole density in the highlands 
above Falling Springs is estimated to be as high as 56 
sinklioles/km- (Panno et al. 2009b). 

Figure 17 A well-manicured sinkhole pond on uplands above 
Falling Springs showing a nearly perfect circle. (Photograph 
by Samuel V. Panno.) 

Figure 18 A more typical sinkliole of the sinkhole plain 
showing the center of the depression is a tangle of oak trees 
and smaller vegetation. (Photograph by Samuel V. Panno.) 

Stop 2: Sparrow Creek Cave Spring, Carondelet, Illinois 

Figures A3 and A4 show the location of sinkholes on 
the highlands that we will visit on the way to Sparrow 
Creek Cave Spring. These aerial photographs from 
1 940 and 2005 reveal the karst terrain and development 
of the area surrounding the spring. The sinkholes are 
most obvious in the 1 940 photograph during drought 
conditions. The sinkhole shown in Figure 17 is promi- 
nent in both photographs, but the surrounding sinkholes 
are very clearly visible in the 1940 photograph. 

Sparrow Creek Cave Spring, located near East Cardon- 
delet, Illinois, is a partially submerged, 5-m-wide, 2-m- 
high opening at the base of a steep, loess-covered, blind 
stream valley (Figure 19). The stream issuing from the 

cave opening is the resurgence of the Stemler Cave 
groundwater basin, the headwaters of Sparrow Creek, 
and one of the largest springs in the state. The ground- 
water basin is about 7 km long and 2 km wide with an 
area of approximately 18 km- (Aley et al. 2000). Spar- 
row Creek Cave is hydrologically connected to Stemler 
Cave to the south. Sparrow Creek Cave consists of a 
245-m-long, northwest-trending passage that leads to 
a sump and a 300-m-long side passage that becomes 
constricted at its distal end (Sherrill 1989). At low flow, 
water discharges from the cave at a rate of about 470 
L/s (Panno et al. 2001 ). The highest discharge measured 
at Sparrow Creek Spring was 1 1,360 L/s following a 
heavy rainfall (Sherrill 1989). 


Figure 19 Sparrow Creek Cave Spring, one of the largest springs in the sinkhole plain, is located 
near Carondelet just northeast of Columbia, Illinois. (Photograph by Samuel V. Panno.) 

Stop 3: Stemler Cave Woods Nature Preserve, Columbia, Illinois 

Figures A5 and A6 show the location of Stemler Cave 
Woods Nature Preserve as it appeared on aerial photo- 
graphs from 1940 and 2005. Both photographs reveal 
the karst terrain on the highlands. The 2005 photograph 
shows the greater extent of the forested area and the 
sinkholes within. Again, the 1940 photograph is much 
better at showing the sinkholes within agricultural areas 
due to the dry conditions of the time. 

Stemler Cave was named after the landowners on 
whose property the cave entrance was located (Figure 
20). The property was initially settled by the Stemlers 
back in the early 1800s. Until the 1950s, the cave was 
used to store eggs and dairy products because of its 
cooler temperatures during summer. Stemler Cave and 
its extension, Sparrow Creek Cave, are branchwork- 
type caves, developed within the St. Louis Limestone, 
that drain the Stemler Cave groundwater basin. The 
crevice entrance of Stemler Cave is 1 5 m long and 5 
m wide and is oriented in an east-west direction. The 
main trunk of Stemler Cave is approximately 1.8 km 
in length and trends northwest-southeast (Webb et al. 
1998b); the cave parallels the axis of the Waterloo- 
Dupo Anticline. Dye tracing shows that the cave prob- 
ably extends to the south, but a zone of collapsed rock 
prevents access to the upstream passages. During low 
flow, groundwater flows through Stemler Cave at a 

rate of 1 50 L/s; downstream in the groundwater basin, 
about three times that volume discharges from Sparrow 
Creek Cave (Panno et al. 2001). During periods of high 
flow, Stemler Cave completely floods, and the brown, 
sediment-laden water backs up 6 m or more in its 23-m- 
deep sinkhole entrance. The cross section morphology 
of Stemler Cave passages is predominantly elliptical, 
suggesting a phreatic origin for the cave. The log cabin 
on the property is a rare two-story cabin that was built 
by German immigrant Johann Georg Stemler in 1836 
(Figure 21). 

In 1986, the Stemler Cave Woods Nature Preserve, a 
120-acre remnant of old growth, dry upland forest was 
dedicated and is maintained by the Illinois Depart- 
ment of Natural Resources. Sinkholes in the area create 
microclimates that result in black and white oak trees 
dominating the upper parts of the sinkholes and red oak 
trees dominating the lower parts. In 2004, thanks to 
extensive efforts by The Karst Conservancy of Illinois, 
the nature preserve (now over 4,500 acres) and the 
Stemler Cave groundwater basin received a Class III: 
Special Resource Groundwater designation from the Il- 
linois Environmental Protection Agency in order to help 
protect the biodiversity of the cave and karst system (Il- 
linois Environmental Protection Agency 2005). 


Stop 4: Columbia Saline Spring, Columbia, Illinois 

There are at least two saline springs in the sinkhole 
plain: one located near Columbia, Illinois, along the 
crest of the Waterloo-Dupo Anticline and the other near 
the Village of Valmeyer (Salt Lick Point) along the 
crest of the Valmeyer Anticline. Saline springs were 
extremely important to the survival of settlers in the 
area during the 1 700s and early 1 800s. Salt was needed 
to preserve meat and fish during the warmer months 
because of the lack of refrigeration. Because of the 
isolated nature of the midwestem United States during 
that time, settlers had to either obtain salt from local 
sources or buy salt from nearby salt works. At that time, 
the only sources of salt in the Midwest were saline 
springs. In about 1850, most small salt works went out of 
business because of the influx of cheaper salt from the 
Kanawha salt works in West Virginia (Kurlansky 2002). 
The perceived medicinal properties of the saline springs 
were exploited between 1850 and 1875, and mineral 

Figure 20 The entrance to Stemler Cave, like the entrance to 
Illinois Caverns, is an east-west-trending solution-enlarged 
crevice at the bottom of a sinkhole. Stemler Cave is located 
just east of Columbia, Illinois (from Panno et al. 1999). 

spas similar to those of Europe sprang up around the 
country at many saline springs. These were extremely 
popular, but only a few are still in business today (e.g., 
the posh West Baden Springs Hotel in southern Indi- 
ana). However, most of these spas went out of business 
in the early 1 900s with the advent of modem medicine 
and financial problems related to The Great Depression 
(Panno etal. 2010). 

There is no record of the use of Columbia Spring (Fig- 
ure 22) as a source of salt during this period. However, 

Figure 21 This two-story log cabin was built by the Stemlers 
in 1 836 and overlooks a large sinkhole just to the south that is 
the entrance to Stemler Cave. The property was chosen by the 
Stemlers in order to use the cave for storage of eggs and dairy 
products during summer months (Homer Stemler, personal 
communication 1995). (Photograph by Samuel V. Panno.) 

Figure 22 Columbia Saline Spring is located just south of 
Columbia, Illinois, and discharges groundwater with a salt 
(NaCI) concentration of about 1 1,600 mg/L. Iron sulfide (FeS) 
precipitates on the stream gravels within and downstream of 
the spring, and white, filamentous, sulfiir-oxidizing bacteria 
form mats at the mouth of and downstream of the spring 
(from Panno et al. 1999). 


it has been reported that a salt works was developed at 
a saline spring along the base of the Mississippi River 
bluff near Valmeyer, Illinois, at a location known as Salt 
Lick Point. The saline springs at that location were used 
by Native Americans and settlers; the springs are no 
longer there and may have been destroyed as a result of 
limestone mining from the late 1800s until about 2000. 
The site of these springs is now part of a 240-ha Salt 
Lick Point Land and Water Reserve developed by the 
Village of Valmeyer. Another saline spring salt works 
near Chalfin Bridge (now Chalfin Bridge, Illinois) in 
Monroe County has been described in the literature 
(Fliege 2002). During the time that the salt works was 
reported to have operated, Chalfin Bridge was a small 
bridge crossing Maeystown Creek located 4.8 km south 
of Monroe (Hackworth 1883). However, a local histori- 
an expressed doubts that such a salt works ever existed 
at Chalfin Bridge. 

The only known saline spring still flowing in the area 
is located just southeast of the city of Columbia, Il- 
linois. Columbia Saline Spring is a small saline spring 
in a wooded area that discharges to a small stream. The 
spring is located along the Waterloo-Dupo Anticline in 
the vicinity of petroleum exploration and production. 
Petroleum deposits associated with traps within the 
Ordovician Kimmswick Formation along the anticline 
have been produced in this area since the 1920s (Brian 
Trask, ISGS, personal communications 2010). Petro- 
leum in the area is located in traps within the Mississip- 
pian and Pennsylvanian strata along the Waterloo-Dupo 
Anticline. Subsequent gas storage activities known 
as the Waterloo Project that occurred between 1951 
and 1973 (Buschbach and Bond 1973) may have initi- 
ated and/or increased flow at the spring. However, the 
fact that the chemical composition of the spring has 
remained constant over the past 15 years suggests the 
spring is a natural feature. 

Figures A7 and A8 show the location of the Columbia 
Saline Spring as it appeared on aerial photographs 
from 1940 and 2005. No karst features are visible 
in the photographs because the area is underlain by 
Mississippian-age Warsaw Formation and Salem 
Limestone. The rocks (carbonate rock and shale) of the 
Warsaw Formation are visible in the bluffs and creek 
bed near the saline spring. The 2005 photograph more 
clearly shows the streams and spring locations. The 
spring is located at a tight bend in a small stream and 
occurs along a prominent east-west-trending lineament 
(Panno, unpublished data). Columbia Spring was an el- 
liptical depression in a stream valley located along the 
headwaters of Carr Creek about 4 km south-southeast 
of Columbia, Illinois. Until about 2005, the depression 
was 1 m long, 5 m wide, and 1 m deep, and it was 

Figure 23 White mats of sulfUr-oxidizing bacteria take up 
white native sulfur within their filaments resulting in a strik- 
ing contrast between the dark, sulfide-coated stream bed and 
the snowy white filamentous bacteria. (Photograph by Samuel 
V. Panno.) 

lined with limestone cobbles coated with a black iron 
sulfide precipitate (Figure 22). Today, the depression 
has been filled with stream gravels by floodwaters, and 
the saline water discharges from a depression within 
the stream and from beneath the gravels that filled the 
original depression. The spring has a strong hydrogen 
sulfide (H^S) odor and discharges from one of the edges 
of the depression where thick mats of white, filamen- 
tous, chemolithoautotrophic, sulfide-oxidizing bacteria 
are present (Figure 23). These bacteria are common 
at saline springs throughout the Illinois Basin (Panno 
et al. 2010) and typically consist of filamentous Epsi- 
lonproteobacteria and Gammaproteobacteria (Engel et 
al. 2004). Members of this group of sulfur-oxidizing 
bacteria consume H^S and, during metabolism, gener- 
ate sulfuric acid; these bacteria have been implicated 
in sulfuric acid speleogenesis (Engel et al. 2004). The 
H,S concentration discharging from the sediment im- 
mediately adjacent to the spring was measured by the 


authors at 3 ppm. The threshold for detecting H,S in air 
is 0.00047 ppm (Powers 2004). Concentrations of 10 to 
20 ppm can lead to eye irritation; 100 to 150 ppm can 
deaden the sense of smell, cause eye damage, and cause 
coughing; 250 to 500 ppm causes nausea, disorienta- 
tion, and pulmonary problems; and concentrations from 
500 to 1,000 ppm can cause rapid loss of conscious- 
ness and death (U.S. Environmental Protection Agency 

Immediately downstream of the spring, there are thick 
bacterial mats that appear white because the some of the 
filamentous bacteria contain native sulfur (orthorhom- 
bic) (Figure 23). During dry summer months, particles 
of native sulfur can be seen in such abundance that the 
stream takes on a milk color (Figure 24). The white fila- 
mentous bacteria extend for about 0.2 km downstream 
where their white strands are in stark contrast to the 
sulfide-blackened bedrock and gravels. The pronounced 
depression and shape of the original spring location in- 
dicated that it was probably a dissolution feature. That 
is, saline groundwater coming up from depth mixed 
with shallow calcium-bicarbonate-type groundwater 
and formed a more aggressive water capable of dis- 
solving limestone due to mixing corrosion (e.g.. Back 
et al. 1986) and/or by bacterially mediated sulfuric acid 
formation that dissolved the underlying the carbonate 
rock. The chemical composition of the spring is NaCl- 
type water with Na and CI concentrations of 3,5 1 and 
8,080 mg/L, respectively. The spring water is slightly 
acidic (pH 6.7) and is discharging from Mississippian- 
age limestone along the axis of the Waterloo-Dupo 
Anticline. The CI/Br ratio of the spring water suggests 
a relatively deep origin, perhaps a mixture of saline 
groundwater from Ordovician and Cambrian strata. 

Saline springs are indicators of preexisting pathways 
from deep within the basin to the surface, which is an 
important consideration when sites are being selected 
for facilities for geologic sequestration of CO,. Panno et 
al. (2010) determined that saline springs found through- 
out the Illinois Basin were located along geologic struc- 
tures within and at the margins of the Basin. Approxi- 

Figure 24 During summer months and at low flow, the 
stream becomes filled with particulates of native sulfiar and 
becomes milk colored. (Photograph by Samuel V. Panno.) 

mately 40 saline spring locations have been identified, 
and we are currently sampling them and using their 
halide ratios and stable isotope and chemical composi- 
tions to determine their source formations. Many saline 
springs are now located in state parks because of the 
unusual nature of the geology and hydrogeology of 
these sites. A few are located at remaining mineral spas, 
and the others are only locally known and are located 
on private lands. 

Stop 5: Camp Vandeventer, Waterloo, Illinois 

Camp Vandeventer is located 6 km west of Waterloo, 
Illinois, and is owned by the Boy Scouts of America 
(BSA). The camp provides outdoor activities for the 
scouts amid an intensely karstified landscape. Figures 
A9 and AlO show the location of the Camp Vande- 
venter as it appeared on aerial photographs from 1 940 
and 2005. The 2005 photograph most clearly shows the 

karst features within the forested areas and the highly 
angular nature of Fountain Creek. The camp straddles 
Fountain Creek, a relatively large stream that dissects 
part of the sinkhole plain (Figure 25). The BSA rented 
this site until 1928; at that time. Judge Wilton M. 
Vandeventer of East St. Louis purchased 27.5 ha and es- 
tablished a permanent camp for the scouts (Voris 1998). 


Figure 25 Limestone bluffs of the well-bedded St. Louis Formation bound Fountain Creek and 
show numerous dissolution features. (Photograph by Samuel V. Panno.) 

The camp is a picturesque geological setting containing 
limestone canyons and bluffs, numerous sinkholes and 
sinkhole ponds, a karst window, caves, springs, and a 
seasonally sinking and resurgent stream. The beds of 
limestone exposed throughout Camp Vandeventer be- 
long to the Mississippian-age St. Louis Formation. 

The winding entrance road passes by numerous sink- 
holes that display a wide range of sizes, depths, and 
types. Across from the Apache Camp site (on the road) 
is a 14-m-deep karst window (Figures 26 and 27). A 
karst window is a sinkhole that forms as a result of the 
collapse of a cave roof to land surface. The water flow- 
ing through this karst window continues to the west as 
a cave stream and discharges at a spring at the base of a 
12- to 14- m bluff just below the camp's old mess hall 
to Fountain Creek (Figure 28) (Aley and Aley 1998). 
Following a particularly heavy rainfall event (e.g., 5 cm 
in 8 hours or less), the karst window fills with runoff, 
overflows, and spills into a ravine leading to Fountain 

Fountain Creek is the largest stream in Monroe County 
and can be quickly transformed into a raging torrent by 
runoff from heavy rainfall. During times of low flow. 
Fountain Creek is a sinking or losing stream. Voris 
(1998) reported that, during particularly dry periods, 
the stream may flow completely underground for a 
few hundred meters downstream of the mess hall. The 
creek water returns to the surface channel about 0.4 km 

downstream and eventually flows into the Mississippi 
River about 16 km west of Camp Vendeventer. Rainfall 
and snowmelt on the plateau drains, for the most part, 
into nearby sinkholes and discharges into Fountain 
Creek via numerous springs along the base of the bluffs 
along the creek including those of Camp Vandeventer. 

The spring at the base of the 12- to 14-m-high bluff lo- 
cated just below the camp's mess hall discharges from a 
small cave in the St. Louis Limestone (Figure 28). Dis- 
charge from the spring was measured at 35 L/s at low 
flow (Aley and Aley 1998). The spring flows directly 
into Fountain Creek through an entrenched channel that 
at one time was the water source for the camp. As with 
most springs in the sinkhole plain, water samples from 
this spring are always contaminated with fecal coliform 
bacteria; the spring is among the most severely contam- 
inated in the sinkhole plain. The dominance of Esch- 
erichia coli and the presence of optical brighteners in 
the spring water suggest that private septic systems are 
a primary source of contamination (Panno et al. 2001; 
Joan Bade, sanitarian, Monroe and Randolph County 
Health Departments, personal communications 1997). 
The rRNA source tracking suggested both human and 
pig sources (W.R. Kelly, Illinois State Water Survey, 
unpublished data). 

Another cave is located just to the west of the spring 
along the same bluff (Figure 29). Usually, discharge 
from this cave is almost negligible. However, the spring 


Figure 26 The karst window at Camp Vande- 
venter formed when the roof of a cave collapsed 
and formed this 1 1 -m-deep cavity. Groundwater 
flows from the far side of the window, disap- 
pears into the near side, and flows to Camp 
Vandeventer Spring. (Photograph by Samuel V. 

Figure 27 View of the karst window from the 
bottom. Moss on the rocks and lower parts of 
the walls suggest the presence of a microclimate 
in this area. (Photograph by Samuel V. Panno.) 

Figure 28 Camp Vandeventer Spring, located at the base of 
the limestone bluff just below the camp's mess hall, is a typi- 
cal large cave spring in Illinois' sinkhole plain. (Photograph 
by Samuel V. Panno.) 

Figure 29 Geochemist Keith Hackley examines collapsed 
slabs of limestone just outside of a small cave spring adjacent 
to the Camp Vandeventer Spring. (Photograph by Samuel V. 


is an overflow for the Camp Vandeventer Spring during 
flooding (Panno et al. 1996), when discharge is charac- 
teristically high-energy, turbulent flow, and both springs 
discharge many hundreds to > 1 ,000 L/s. 

The bluff on the opposite side of Fountain Creek is a 
classic exposure of St. Louis Limestone that displays 

numerous dissolution features (Figure 25). The upper 
portion of the bluff contains vertical joints that allow 
surface water to move downward into bedrock. Small 
amounts of water move laterally along bedding planes 
and can be seen discharging from the bluff wall and 
flowing down the bluff face. A small, sediment-filled 
cave passage is visible at the base of the bluff. 

STOP 6: Fountain Creek Stone Bridge, Waterloo, Illinois 

Figures Al 1 and A12 show the location of the Foun- 
tain Creek Stone Bridge just to the south of Camp 
Vendeventer as it appeared on aerial photographs from 
1940 and 2005. Although this bridge is no longer in 
use, it has been preserved and is located just south of 
Route 156 about 3 km west of Waterloo and can be 
seen just south of the roadway. A trace of the old road 
that crossed the stone bridge is still visible on the 1940 
photograph. Karst features surround the bridge, and the 
angular nature of Fountain Creek is most apparent in 
the 2005 photograph where the stream orientation cor- 
responds to lineaments and solution-enlarged crevice 
orientations. The stone bridge was one of the first built 
in Monroe County (1849) ft^om limestone quarried from 
the area and is one of the largest in the area (Figure 
30). The bridge was used to cross Fountain Creek until 
1927. Similar arched stone bridges are common in the 
sinkhole plain. Early settlers to southwestern Illinois 
took advantage of the abundance of limestone in the 
area for construction of houses, buildings, and bridges 
and as lining for hand-dug wells (Figure 31). A few 
houses and numerous arched stone bridges can still be 

seen in southwestern Illinois. Today, limestone quar- 
ries are common features in the sinkhole plain, and the 
limestone is used for aggregate and building materials. 

Figure 31 This now abandoned building at Valmeyer Quarry 
is another example of the use of natural materials for con- 
struction in southwestern Illinois (Panno et al. 1999). 

Figure 30 Fountain Creek Stone Bridge, located just west of 
Waterloo, Illinois, on Route 156, was built from locally quar- 
ried limestone in 1 849. (Photograph by Samuel V. Panno.) 

Figure 32 Chert is commonly found as masses and in tabular 
form along beds of the Upper St. Louis Limestone (here along 
the bluffs of Fountain Creek) and was used by Native Ameri- 
cans in the area. (Photograph by Samuel V. Panno.) 


Upstream of the bridge is an excellent exposure of the 
upper St. Louis Limestone showing prominent, thin 
bedding planes and abundant chert weathering out of 
the rock (Figure 32). Chert was used by Native Ameri- 
cans in the area for tools and other implements. Along 
several of these bedding planes, there is evidence of 
dissolution and groundwater discharge to the stream. 
Numerous anastamoses, small springs, and small caves 
can be seen. During low flow, a prominent limestone 
bed provides a pavement that makes for easy walk- 
ing upstream. Within this pavement, a small spring 
discharging from the base of the bluff has created an 
incised channel about 10 cm wide and 10 cm deep that 
meanders like a stream channel (Figures 33 and 34). 
We suggest that the channel initially formed along a 
bedding plane where its pathway was affected by the ir- 
regular surface of the limestone bed. The channel is 
actively being downcut by aggressive shallow ground- 
water from locally recharging rainfall and snowmelt 
and abrasion by sediments. Just upstream. Fountain 
Creek makes a sharp 90 degree turn to the east (Figures 
A 1 1 and A 1 2); because this is one of several angular 

Figure 33 The bluffs of Fountain Creek reveal many karst 
features, including caves and springs. The Fountain Creek 
stream bed, seen here just south of the stone bridge, is a bed- 
ding plane surface on which dissolution features may be seen. 
To the left of the photograph is a small spring that discharges 
from the base of the bluff and created a sinuous incised chan- 
nel to the stream. (Photograph by Samuel V. Panno.) 

Figure 34 (a) The incised channel (from Figure 33) showing the relationship between the sinuosity and the texture of the surface 
of the bedding plane. The inset of this channel reveals the stream-like details of the channel, (b) Detail of the incised channel 
showing organic debris within the channel and preferential dissolution and abrasion along the leeward sides of the meanders 
(Photograph by Samuel V. Panno.) 


Figure 35 Nick point just after a 90 degree turn in Fountain Creek just upstream from the in- 
cised cliannel showing the tabular bedding of the St. Louis Limestone. (Photograph by Samuel 
V. Panno.) 

turns for this creek, and because one of the dominant 
joint directions in the sinkhole plain is east-west, it 
is likely that the trace of Fountain Creek is joint con- 

trolled. Just beyond that point, a nick point in the lime- 
stone has created a small steplike waterfall that reveals 
bedding of the St. Louis Limestone (Figure 35). 

Stop 7: Rock City, Valmeyer, Illinois 

Rock City is a joint venture of the Village of Valmeyer 
and Admiral Parkway Inc. that rents the now closed 
Valmeyer Quarry as storage space. The Village of Val- 
meyer was originally located on the floodplain of the 
Mississippi River but was destroyed by a 1 .5-m wall 
of water and associated flooding that resulted from a 
breached levy during the Great Flood of 1993. With the 
help of federal grants, the village relocated in a karst 
area on top of the bluff overlooking the Mississippi 
River and created infrastructure for the new Village of 
Valmeyer and for Rock City. 

Quarrying operations of the former Columbia Stone 
Company ceased in 1992 after operating for more than 
120 years (Figure 36). The quarrying operations were 
conducted along the Mississippi River bluffs in the 
late 1800s and early 1900s, and the rock was used for 
agriculture soil amendments and roadbed ballast for the 
Missouri-Pacific Railroad. Mining later went under- 
ground extracting the Ordovician-age Dunleith Forma- 

Figure 36 Mine openings in massive Ordovician-age lime- 
stone are commonly seen along the blufifs of the Mississippi 
River near the Village of Valmeyer. These mines are currently 
being used for storage and refrigeration at Rock City. (Photo- 
graph by Samuel V. Panno.) 


tion of the Kimmswick Subgroup (Figure 37). The rock 
is a coarse-grained, light gray to white limestone that 
is about 30 m thick in this area and is exposed along 
the crest of the Valmeyer Anticline. Mississippian- 
age rocks are exposed along both flanks (Frankie et 
al. 1997). The limestone that was mined is massive in 
character with no apparent karst features. Figures A13 
and A 14 show the location of Rock City as it appeared 
in USGS NAPP aerial photographs from 1940 and 
2005. The 1940 photograph shows the quarrying opera- 
tions as white patches, and the 2005 photograph shows 
the Rock City operations as they appear today. 

Currently, the Rock City operation has 557,400 m^ of 
area within the old mine workings. As much as 465,000 
m- of this area has been taken up by the National Ar- 
chives and Records Administration for storage of retired 
military personnel records and other materials. Another 
18,600 m- has been converted to a cold (frozen) storage 
space. Here, foods such as Girl Scout cookies, pizza, 
and ice cream products are stored until they are ready 
for distribution (Lori Magg, manager of Rock City, per- 
sonal communications, 2010). 


The authors thank Cheryl Nimz and Michael Knapp 
(ISGS) for their efforts in editing, compiling, and print- 
ing this document. We thank Donald Keefer (ISGS), 
Mirona Chirienco (University of Illinois), and Timothy 
Larson (ISGS) for their reviews of the manuscript and 
excellent suggestions, and the following landowners for 
allowing us to enter onto their lands prior to and dur- 
ing the field trip: Mary Gail Ketten (Falling Springs), 
Eric Harr (Sparrow Creek Spring), Bob Week (Stemler 
Cave), Fred Easter (Columbia Saline Spring), Ranger 
Shane Sellers and the Boy Scouts of America (Camp 

Figure 37 The limestone along the Mississippi River bluffs 
were mined using room and pillar methods with ceiling 
heights of 10 m. Mining from the early 1870s to 1992 resulted 
in over 500,000 m' of mined out area (Photograph by Samuel 
V. Panno). 

Vandeventer), Chris Graves (Fountain Creek Stone 
Bridge), and Lori Magg (Rock City). We also thank the 
following speakers from the area for their willingness 
to share their historical and technical knowledge with 
the participants of the field trip: Cliff LePere (Falling 
Springs), Bob Week (Stemler Cave), Shane Sellers 
(Camp Vandeventer), Joan Bade and John Wagner (ef- 
forts by the local Health Departments), Merrill Prang 
(Fountain Creek Stone Bridge), and Joseph Koppeis 
(Rock City). Finally, we thank Barry Beck of P.E. 
LaMoreaux and Associates for his insightful decision 
to make field trips an integral part of these conferences. 
Preparation and publication of this field guide were 
funded by the Illinois State Geological Survey and by 
P.E. LaMoreaux and Associates. Publication of this field 
guide has been authorized by the Director of the Illinois 
State Geological Survey. 


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Appendix: Aerial Photographs 

Figure Al USGS National Aerial Photography Program (NAPP) aerial photograph of the Falling Springs and upland karst area 
acquired on March 3, 2005. 


500 1,000 1,500 ft i 

100 200 300 400 m I 

Figure A2 USDA Agricultural Adjustment Administration (AAA) aerial photograph of the Falling Springs and upland karst area 
acquired on June 25, 1940. 


Figure A3 USGS NAPP aerial photograph of the Sparrow Creek Cave Spring and upland karst terrain acquired on March 3, 


Figure A4 USDA-AAA aerial photograph of the Sparrow Creek Cave Spring and upland karst terrain acquired on June 25, 


Figure A5 USGS NAPP aerial photograph of the Stemler Cave Woods Nature Preserve area and associated karst terrain acquired 
on March 3, 2005. 


500 1,000 1,500 ft I 
|,',l,',),',t|',l,' J ,',,i,^,i M , i |i, M |l,i, M,M ,i | i,i,i| l II 
100 200 300 400 m I 

Figure A6 USDA-AAA aerial photograph of the Stemler Cave Woods Nature Preserve area and associated icarst terrain acquired 
on June 30, 1940. 


Figure A7 USGS NAPP aerial photograph of the Columbia Saline Spring area acquired on March 3, 2005. 


Figure A8 USDA-AAA aerial photograph of the Columbia Saline Spring area acquired on June 25, 1940. 


Figure A9 USGS NAPP aerial photograph of the Camp Vandeventer area and associated karst terrain acquired on March 3, 


Figure AlO USDA-AAA aerial photograph of the Camp Vandeventer area and associated karst terrain acquired on September 5, 


500 1.000 1,500 ft 4 

| , ' , 1,' J .'. l |' . l.'.|l. 'ii i o.| .tii|i.| .t i''i'''i'''i''i''''''' N 

100 200 300 400 m I 

Figure All USGS NAPP aerial photograph of the Fountain Creek Stone Bridge area and associated karst terrain acquired on 
March 6, 2005. 


Figure A12 USDA-AAA aerial photograph of the Fountain Creek Stone Bridge area and associated karst terrain acquired on 
Septembers, 1940. 


Figure A13 USGS NAPP aerial photograph of the Rock City area acquired on February 25, 2005, showing the roadways and 
parking area of the new storage facilities. 


Figure A14 USDA-AAA aerial photograph of the Rock City area acquired on July 17, 1940, showing the areas where mining 
operations were taking place (white patches).